1. Field of the Invention
The present invention relates to an apparatus and method for applying component parts of a sealant which when mixed transforms from a fluidic state to a non-fluidic state. In particular but not exclusively, the present invention is directed to an apparatus and process in which sealant components are mixed prior to being applied to biological tissue to effect hemostasis or achieve other therapeutic results.
2. Description of Related Art Including Information Disclosed under 37 CFR 1.97 and 37 CFR 1.98
Use of tissue sealants and other biological materials is an important emerging surgical technique, well adapted for the operating room or field environments such as the doctor's office or mobile medical units. In addition, the application of such sealants via a catheter provides a non evasive medical technique. Preferred sealants include fibrin sealants which are formed from blood plasma components and comprise, on the one hand, a first component containing fibrinogen and Factor XIII and on the other hand a second component which usually includes thrombin, and calcium ions.
The fibrinogen is capable of a polymerizing and being cross-linked to form a solid fibrin clot when the components are mixed. The necessary additional factors to simulate relevant portions of the natural blood coagulation cascade are suitably distributed between the fibrinogen and thrombin components.
High levels of protection against transmission of infections or induction of immunological reactions can be assured by using an autologous or single-donor source for both components. Such sealants are highly effective, are biologically degraded without residue and may promote wound healing.
Depending upon the potency of the particular formulations employed, coagulation of the sealant may take place very rapidly, yielding a gel within perhaps 10 or 20 seconds after mixing of the two components. Though often very desirable for surgical reasons, such fast-acting properties present potential problems of fouling or clogging. These problems must be overcome in devising suitable applicators, and methods of application.
A popular manually operable applicator for such two-component sealants employs a dual syringe construction wherein two syringes, connected by a yoke, each provide a reservoir for one of the components. In most prior devices, the sealant components are discharged in separate streams and mixed externally of the applicator. Such applicators are similar in principle to household epoxy glue applicators commonly available in hardware stores. Achieving effective mixing externally of the applicator is problematic.
In U.S. Pat. No. 5, 266,877, and the above applications, the present inventor teaches various constructions of a dual syringe applicator wherein the fluid sealant components are mixed internally.
Antanavich et al. U.S. Pat. No. 5,585,007, whose disclosure and references are hereby incorporated herein by reference thereto, provides an extensive discussion of the literature relating to fibrinogen sealant preparation (column 1, line 20 to column 4, line 62) and applicators column 4 line 62 to column 5, line 14), as well as a bibliography, (columns 6-10) and is a helpful guide to the teachings of prior workers in the field.
In one or more of the above copending applications the possibility of retrograde clearing of the mixed fluids pathway within the applicator, using suction, is also disclosed. The applicator is provided with suitable suction conduits and valving to apply suction to the work surface, to prepare it for the application of sealant, for example by removing fluids. As taught, the valving is operable to effect retrograde clearing of a sealant dispensing pathway. Enhanced mixing is possible for example, by impingement and problems of fouling by deposited solids are avoided.
Such applicators, and methods, are remarkably effective for applying sealants to exposed biological surfaces. However, it would be desirable to provide a surgeon, or other user, with additional choices, for example, an applicator and method that could effectively apply sealant to internal biological locations.
One difficulty is that the coagulating nature of the sealants causes the discharge opening or openings of an application device to become clogged so that flow out of the applicator slows down or stops.
While the above-referenced copending applications disclose effective clearing-enabled sealant application devices and methods, their techniques are generally intended for application of sealant to exposed and accessible work surfaces.
There is accordingly a need for a sealant applicator and method that can be used to reach an unexposed or inaccessible location.